In the past, sphenoid sinusitis was considered a rare nasal disease. According to Liu Junqian's (1958) observation of 660 cases of nasal sinus X-rays, there were only 6 cases of isolated chronic sphenoid sinusitis, accounting for 0.9%. Due to the deep location of the sphenoid sinus, insufficient illumination during nasal endoscopy made it difficult to visualize its opening, coupled with the nonspecific symptoms of sphenoid sinusitis, it was believed to have the lowest incidence rate. In recent years, the advent of cold light source nasal endoscopes has allowed the use of various angles to improve illumination and visibility within the nasal cavity, overcoming the limitations of the visual field. As a result, the incidence of chronic sphenoid sinusitis has significantly increased. According to data from Zhao Chuoran et al. (1988), among 700 routine nasal endoscopic examinations, 58 cases of sphenoid sinusitis were found, accounting for 8.3%.

bubble_chart Etiology

Same as chronic ethmoid sinusitis.

bubble_chart Pathological Changes

Based on 58 cases of nasal endoscopy, isolated sphenoid sinusitis accounted for 34%, coexisting with posterior ethmoid sinusitis in 14%, with anterior sinusitis in 19%, and with pansinusitis in 33%.

bubble_chart Clinical Manifestations

Some patients with this disease have no complaints or only insignificant symptoms. Careful inquiry may reveal the following symptoms:

1. Headache - Often located behind the eyeball, particularly in the vertex and occipital region, worsening at night or after alcohol consumption.

2. Reflex neuralgia - May include trigeminal neuralgia, toothache, or neuralgia in the mastoid, neck, shoulder, and back regions.

4. Dizziness - Unsteady gait with swaying but no directional deviation, differing from vestibular vertigo.

5. Postnasal drip - Purulent discharge may flow from the posterior nasal cavity to the pharynx when bending the head or changing head position, with temporary relief after expectoration.

Examination - Traditional examination involves applying topical anesthesia to the nasal cavity and inserting a long nasal speculum to push the middle turbinate laterally. Occasionally, purulent discharge can be seen at the sphenoid sinus ostium, along with pus in the olfactory cleft. The sphenoethmoidal recess shows congested mucosa, and the posterior pharyngeal wall exhibits thickened, congested mucosa with purulent discharge at the posterior nasal cavity. However, due to poor illumination, observation is often difficult.

Fiber-optic nasal endoscopy, reveals mucosal edema and polypoid changes in the superior nasal meatus and sphenoethmoidal recess, along with purulent discharge. The sphenoid sinus ostium may be obstructed by polyps, and after decongestion, mucosal congestion and purulent discharge become visible. Due to its high visibility, pathological changes are easily detected.

bubble_chart Diagnosis

1. Conservative Therapy Negative pressure replacement has shown relatively good results. An appropriate amount of antibiotics, corticosteroids, and enzyme preparations can be added to a 1% Ephedrine solution.

2. Surgical Therapy

1. Sphenoid Sinus Irrigation Indicated for chronic sphenoid sinusitis when conservative therapy is ineffective, examination reveals obstruction of the sphenoid sinus ostium, poor drainage, and significant symptoms.

(2) A calibrated catheter with a slightly curved tip is inserted obliquely upward through the olfactory cleft of the nasal cavity until it reaches the cribriform plate. It is then moved posteriorly until it reaches the anterior wall of the sphenoid sinus. When the catheter crosses the center of the lower edge of the middle turbinate, it can enter the sphenoid sinus ostium. A 30-degree angled endoscope can be used to guide the catheter into the sphenoid sinus ostium under direct visualization.

(3) A syringe filled with sterile saline is connected to the catheter for initial aspiration. If pus is confirmed, the patient is instructed to lower their head and hold a basin while irrigation is performed. Blind puncture and irrigation of the sphenoid sinus are dangerous and should not be attempted.

2. Sphenoid Sinus Ostium Enlargement Indicated for cases where irrigation of the sphenoid sinus using the above method is difficult.

(1) Local anesthesia is performed as described above. The middle turbinate is pushed laterally to expose the anterior wall of the sphenoid sinus. If necessary, the posterior part of the middle turbinate is resected to improve visibility.

(2) A hooked ethmoid sinus knife is inserted into the sphenoid sinus ostium to fracture the lateral bony wall. A rotating sphenoid sinus punch is then used to enlarge the ostium, and bone fragments are removed. If polyps are confirmed within the sinus, they can be excised, but care must be taken to avoid injuring the lateral and superior walls of the sphenoid sinus to prevent complications.

(1) Nasal Septum Approach Bilateral topical anesthesia of the nasal septum is performed. A unilateral mucosal incision is made following the subperichondrial resection technique of the nasal septum. The mucoperiosteum is elevated to expose the anterior wall of the sphenoid sinus. The nasal septal cartilage is incised, and the contralateral mucoperiosteum is elevated posteriorly and superiorly to reach the anterior wall of the sphenoid sinus. The quadrangular cartilage and perpendicular plate of the ethmoid bone are removed to expose the rostrum of the sphenoid sinus. The mucoperiosteum of the anterior wall is further elevated bilaterally to fully expose the anterior wall. A chisel and punch are used to remove the anterior wall of the sphenoid sinus, allowing sufficient opening and drainage. At the end of the procedure, the bilateral mucoperiosteal flaps are repositioned, and both nasal cavities are packed. The packing is removed the next day.

(2) Intranasal Ethmoid Sinus Approach Indicated for chronic sphenoethmoiditis. The method is similar to intranasal ethmoidectomy. After opening the anterior and posterior ethmoid air cells, further posterior exploration reveals the anterior wall of the sphenoid sinus. The anterior wall can be divided into two parts: the ethmoid portion (laterally covered by ethmoid cells) and the nasal portion (medially exposed in the nasal cavity). The ratio of the ethmoid portion to the nasal portion is approximately 5:3. Opening the anterior wall of the sphenoid sinus is not difficult.

(3) External Ethmoid Sinus Approach Indicated for fungal pansinusitis requiring extensive exploration or suspected intracranial or intraorbital infection. For uncomplicated isolated sphenoid sinusitis, this approach is unnecessary.

(4) Maxillary Sinus Approach Suitable for patients with chronic sphenoethmoiditis combined with chronic maxillary sinusitis (see De Lima surgical treatment for chronic ethmoiditis).

(5) Functional Endoscopic Sinus Surgery Approach This new technique has been implemented domestically. Due to improved illumination and visibility compared to traditional methods, the surgical success rate has been significantly enhanced (see Surgical Treatment of Chronic Ethmoid Sinusitis).

bubble_chart Complications

Common Surgical Complications For the various sphenoid sinus surgeries mentioned above, if performed according to standard procedures, complications can be avoided. The key to preventing surgical complications is to avoid grasping pathological tissues within the sphenoid sinus. This is because the superior wall of the sphenoid sinus is adjacent to the dura mater and the pituitary gland, while the lateral wall is closely related to the optic nerve, internal carotid artery, cavernous sinus, and maxillary nerve. Neurovascular structures adhere to the lateral wall of the sphenoid sinus within the cranial cavity, forming indentations on the bony wall and protruding into the sinus cavity as bulges. Sometimes, the bony wall at these bulges is extremely thin or even absent. If pathological tissues on the lateral wall are grasped during surgery, catastrophic consequences may ensue. According to data published by Xu Yu and Wang Jiqun (1994) from 50 cases, bony defects at the optic nerve canal bulge accounted for 2%, and defects at the internal carotid artery bulge accounted for 4%. The optic nerve canal is located at the uppermost part of the lateral wall of the sphenoid sinus, running from posterior to anterior. The internal carotid artery canal lies below the optic nerve canal, curving from anterior to posterior, and is most susceptible to injury during surgery. The pterygoid canal is located on the lateral side of the inferior wall of the sphenoid sinus, surrounded by thicker bony walls, making injury to the pterygoid canal nerve less likely during surgery.

1. Cerebrospinal Fluid Rhinorrhea The bony plate near the posterior ethmoid cells on the roof of the sphenoid sinus is very thin. If the dura mater is injured during surgery, cerebrospinal fluid may leak out. The fluid is clear and transparent; if mixed with blood, a drop on cloth will show a central red clot surrounded by a colorless ring. Laboratory tests indicate protein levels below 20mg/L and glucose levels above 30mg. Treatment involves locating the fistula under nasal endoscopy and sealing it with small pieces of muscle and fascia. The sphenoid sinus can be packed with iodoform gauze. Postoperatively, the patient should be placed in a semi-sitting position, avoid nose blowing, limit fluid intake, and receive broad-spectrum antibiotics that easily cross the blood-brain barrier to prevent infection. The iodoform gauze can be removed 1–2 weeks after surgery. Close monitoring for signs of meningitis or brain abscess is necessary, and prompt treatment should be administered if needed.

2. Optic Nerve Injury The optic nerve is located at the junction of the roof and lateral wall of the sphenoid sinus, specifically the uppermost part of the lateral wall. If surgical instruments touch the optic nerve, the patient may experience flashes of light, and surgery should be halted immediately to check vision. The sphenoid sinus cavity should not be packed to avoid pressure on the optic nerve. Postoperatively, administer dexamethasone at 5mg/kg for three days. Monitor visual acuity; if vision continues to decline, consider performing optic nerve decompression surgery.

3. Internal Carotid Artery Rupture During sphenoid sinus surgery, sudden profuse arterial bleeding indicates internal carotid artery rupture. Immediately pack the lateral wall of the sphenoid sinus with iodoform gauze to apply pressure, terminate the surgery, and return the patient to the ward for blood transfusion. The gauze should be slowly removed after two weeks. If bleeding persists, additional packing or detachable balloon embolization of the ruptured internal carotid artery under fluoroscopy via an arterial catheter may be required.